The present invention relates generally to a multipurpose electromechanical device which provides a pumping function such as might be required in an air conditioning system as well as an electrical energy generating function to obviate the need for, for example, a .[.separatively.]. .Iadd.separately .Iaddend.driven vehicle alternator.
In the past, vehicles have included a prime mover, such as an internal combustion engine, which in addition to supplying energy to drive the vehicle, also provides energy to a number of other devices through a maze of V-belts, pulleys and the like. Specifically, such an engine drives an electrical generator or alternator, a water pump, a power steering pump, an air conditioner pump or compressor, various anti-pollution devices and perhaps other devices.
The typical alternator will be engine-driven by way of a V-belt and a relatively small diamater pulley, for example, of the order of 21/2 inches in diameter. The alternator typically therefor revolves at a relatively high speed generating a relatively high frequency alternating current voltage. With such a relatively high frequency alternating current voltage, stator core losses are relatively high and with such a small diameter pulley, belt slippage is a substantial problem. From at least a size standpoint, larger pulleys and lower frequencies have heretofore not been practical.
Compressors for vehicle air conditioning systems are typically also belt-driven from the engine by way of a pulley, which is selectively coupled to the compressor shaft by an electromagnetic clutch arrangement. Much of the time this electromagnetic clutch is not actuated and the compressor pulley and V-belt are "free wheeling", contributing nothing to the system except frictional losses. As compared to an alternator, the current compressor design is of a lesser number of revolutions per minute, greater pulley diameter (a six inch diameter pulley would not be uncommon) and a somewhat larger overall structure. The larger pulley diameter and slower speed reduces belt slippage and related problems.
It is also known in the prior art, for example, in U.S. Pat. No. 2,660,865 to provide a common shaft for a pump and an electrical generator, however, such prior art approaches amounted to little more than placing the two machines end to end with the overall axial length, weight and cost being substantially the sum of those traits for the respective individual components.